You can download it for Linux, Mac, and Windows

The Mozilla Firefox 63.0 "Quantum" web browser is now available to download for all supported platforms, including Linux, Mac, and Windows, ahead of tomorrow's official launch.

Mozilla plans to unveil the Firefox 63.0 web browser on October 23, 2018, but you can download it right now if you want to be one of the first to use it on your Linux, Windows, or Mac computer. Mozilla Firefox 63.0 continues the "Quantum" series of the popular open-source web browser with a set of new features and improvements.

Highlights of the Mozilla Firefox 63.0 release include support for running WebExtensions in their own process on Linux, which could mean the web browser would consume less memory and CPU usage, and the ability to warn users when there's several tabs and windows open when attempting to quit the browser from the main menu.

For Mac users, Mozilla Firefox 63.0 improves reactivity, speeds up tab switching, and adds new options in the WebGL power preferences to allow non-performance-critical apps and applets to request the integrated GPU instead of the dedicated one on hybrid GPU computers.

For Windows users, Firefox 63.0 also improves Windows 10 integration, which means that you can now match the Firefox theme with your operating system's Dark / Light mode, and adds significant performance gains to the web browser due to using the Clang/LLVM compiler for Firefox's build infrastructure on Windows.

Developer changes, bug fixes, and other improvements

For all supported platforms, Mozilla Firefox 63.0 removes the Open in Sidebar feature for individual bookmarks in the Library, as well as the option to never check for updates from about:preferences (as a substitute, users can use the DisableAppUpdate enterprise policy), and fixes a bug preventing the address bar from automatically filling bookmarked URLs.

Other than that, the Ctrl+Tab shortcut has been updated to show thumbnail previews of your tabs and cycles within tabs in the recently opened order by default in new profiles, but you can change the behavior in preferences. For web developers, this release enables the Dev Tools accessibility inspector by default and adds support for Web Components custom elements and shadow DOM.